1. Field of the Invention
This invention relates generally to a manifold or member for delivering fresh fluid and, more specifically, to a manifold for supplying fresh etchant and removing spent etchant from an article being etched.
2. Description of the Prior Art
In the prior art, the process of etching articles by etchant fluids is well known. A typical process is to use a series of jets or spray nozzles which direct a stream of etchant fluid onto an article to be etched. This process has a drawback in that the impinging fluid stream often contains sufficient momentum so as to dislodge or break away the resist thus causing portions of the protected surface to be etched away.
Another method which does not have the disadvantage of breaking the resist is the immersion etching of the article. That is, by immersing the article to be etched in a tank of etchant, one eliminates the breakage of resist due to the momentum of the etchant. However, in immersion it is usually difficult to continually supply fresh etching fluid to the article to be etched.
However, neither of the processes described, i.e., the utilization of jets or immersion etching has proven entirely effective for etching precision articles, that is, it is difficult to obtain good resolution by either using fluid jets or immersing an article in an etching tank. One of the problems of the utilization of jets which has been most troublesome is that when the fluid impinges on the article to be etched, it also impinges on the resist which oftentimes breaks off portions of the protective resist and thus makes the edges of the article subject to overetching. Consequently, the article which is etched by use of impinging jets will usually have poor resolution. For very precision etching, this type of resolution is not acceptable and particularly in those instances where it is required to accurately etch a hole in an article which has a dimension less than the thickness of the material to be etched through.
The present invention is a discovery that a fluid manifold which has a plurality of sources and sinks can coact to supply a fluid sheet of material to the surface of the article to be etched which results in an article which has a resolution that is considerably better than obtained by the prior art techniques which utilize spray jets.